This invention relates to a protective shield for elongated underground utilities such as an elongated underground utility strand or pipe (i.e. steel pipe, plastic pipe, electric conduit, fiber optic cables and other elongated underground utility strands or pipes). The protective shield protects the elongated underground utilities as they are being laid in a trench, during subsequent back-filling of the trench and covering of the elongated underground utilities, and during prolonged use under a variety of conditions and exposures.
It will be appreciated that care must be taken to avoid damaging elongated underground utilities during the laying of same in trenches. Some elongated underground utilities may be subject to corrosion, scratches, marring or impact while other damage may be due to certain ground conditions and exposures.
Because steel pipe is subject to corrosion, it is usually coated with a plastic material during its manufacture as well as having individual welds coated in the field so as to prevent corrosion. While plastic pipes are not subject to corrosion, they are subject to scratches, marring or impact during the laying of the pipe in a trench, as well as during subsequent back-filling of the trench and covering the pipe. Electrical conduit and fiber optic cable are also subject to damage due to marring or impact during the covering and back-filling of same in a trench. Prolonged use of elongated ground utilities can also result in damage under certain conditions and exposures. For example, in the laying of plastic gas transmission pipe on a rock bed in a trench and the subsequent back-filling over the plastic gas transmission pipe with more gravel and dirt on top of the plastic gas transmission pipe, damage to the pipe may occur when vehicular traffic drives over the back-filled trench a number of times. This can lead to bursting of the pipe and explosions creating significant health risk to humans.
As explained in U.S. Pat. No. 5,099,889, the prior art has developed many ways in which to protect and cover such underground utilities including the use of sand, sand bags, foam plastic pads and poured-in-place foam plastic product. In order to overcome the difficulties and expenses in applying such aforementioned techniques, the external pipe protector of U.S. Pat. No. 5,099,889 was developed. The invention of this aforementioned patent includes an elongated flexible sheet of shock absorbing material that was enabled to be quickly and conveniently wrapped about and fastened in an encircling relationship to an elongated length of pipe. The flexible sheet of shock absorbing material was disclosed as being preferably constructed as a flexible porous mat in order to enable moisture to be dissipated from around the elongated length of pipe, while further permitting cathodic testing of same for crack and rust deposits, by enabling a charged electrical rod to be inserted through the open construction of the flexible porous mat.
While the technique disclosed in U.S. Pat. No. 5,099,889 overcomes many of the problems of the prior art, it nonetheless has been difficult and somewhat labor intensive to wrap the flexible sheet of shock absorbing material around an elongated length of pipe. As will be appreciated, significant manual labor is required in wrapping the flexible sheet of shock absorbing material around the length of pipe and securing same in position to avoid damage to the elongated length of pipe. As a result, there has been a long felt need in the art for an even simpler and less expensive system for quickly and easily applying an effective protective shield, while at the same time minimizing labor costs.